[PATCH 1/1] AF_UNIX: Fix poll locking problem when reading from a stream socket

From: Alexey Moiseytsev
Date: Mon Nov 21 2011 - 18:36:24 EST


poll() call may be locked by concurrent reading from the same stream
socket.

Signed-off-by: Alexey Moiseytsev <himeraster@xxxxxxxxx>
---
net/unix/af_unix.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 466fbcc..b595a3d 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1957,6 +1957,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
if ((UNIXCB(skb).pid != siocb->scm->pid) ||
(UNIXCB(skb).cred != siocb->scm->cred)) {
skb_queue_head(&sk->sk_receive_queue, skb);
+ sk->sk_data_ready(sk, skb->len);
break;
}
} else {
@@ -1974,6 +1975,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
chunk = min_t(unsigned int, skb->len, size);
if (memcpy_toiovec(msg->msg_iov, skb->data, chunk)) {
skb_queue_head(&sk->sk_receive_queue, skb);
+ sk->sk_data_ready(sk, skb->len);
if (copied == 0)
copied = -EFAULT;
break;
@@ -1991,6 +1993,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,
/* put the skb back if we didn't use it up.. */
if (skb->len) {
skb_queue_head(&sk->sk_receive_queue, skb);
+ sk->sk_data_ready(sk, skb->len);
break;
}

@@ -2006,6 +2009,7 @@ static int unix_stream_recvmsg(struct kiocb *iocb, struct socket *sock,

/* put message back and return */
skb_queue_head(&sk->sk_receive_queue, skb);
+ sk->sk_data_ready(sk, skb->len);
break;
}
} while (size);
--
1.7.2.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/